1. Field of the Invention
The invention relates to a method for setting the valve lift of an inlet valve of an internal combustion engine.
In the case of conventional Otto-type engines with throttle-valve load control, full load corresponds to the state in which the throttle valve is fully open. However, the prior art also includes devices for the variable control of the valves of internal combustion engines, in particular for load control of Otto-type engines, by use of the inlet-lift functions of the inlet valves, in which the lift and the duration of opening of the inlet valves can be varied. Various systems are known for this purpose, e.g. Published, European Patent Application EP 0 638 706 A1 or Published, Non-Prosecuted German Patent Application DE 42 44 550 A1. The latter document includes an explanation of a coupler mechanism by use of which two camshafts can be rotated relative to one another. The associated valve is actuated by a transmission lever that senses the cam position of both camshafts, thus allowing the valve lift to be varied. Camshaft adjustment is useful, in particular, in eliminating exhaust and refill losses.
Published, Non-Prosecuted German Patent Application DE 32 10 914 A1 relates to a camshaft control unit for the speed-dependent and load-dependent angular adjustment of a camshaft of an internal combustion engine. Here, a fixed desired value is read out from a desired-value memory as a function of load and rotational speed for the purpose of camshaft adjustment.
International Patent Application WO 95/13458 has disclosed a method for optimizing the charging of a cylinder by varying the closing point of an inlet valve in an internal combustion engine with hydraulic or electromagnetic adjustment of the closing point.